A federal appeals court backed the Obama administration’s campaign to limit greenhouse-gas emissions, in a blow to the coal industry and other companies that say regulators acted without a scientific basis and are stifling job creation.

The court in Washington, D.C., gave the Environmental Protection Agency almost everything it wanted in the 82-page ruling on Tuesday. A three-judge panel unanimously upheld the EPA’s central 2009 finding that greenhouse gases such as carbon dioxide endanger public health and likely have been responsible for global warming over the past half century.

The ruling drew immediate fire from companies that say the EPA exceeded its powers under the Clean Air Act, signed by Richard Nixon in 1970.

A spokeswoman for Atlanta-based Southern Co., SO +0.56% owner of four electric utilities, said the company “continues to believe that the Clean Air Act is ill-suited to handle issues like greenhouse gases, and that Congress should be the policy maker in this area.”

The court’s ruling is likely to echo in this year’s elections, where Republicans, including presidential candidate Mitt Romney, are charging the Obama administration with undermining job growth through tighter environmental rules.

Mr. Romney’s camp this month unveiled a television ad in Ohio, a major coal-mining state, that envisions the first months of a Romney administration and says, “By day 100, President Romney repeals regulations that are strangling our energy industry and costing us jobs.” Mr. Romney has said that he wants to amend the Clean Air Act to strip the EPA of its authority to regulate carbon dioxide.

EPA Administrator Lisa Jackson said the decision was “a strong validation” of the agency’s approach. The court held that “EPA followed both the science and the law in taking common-sense, reasonable actions to address the very real threat of climate change by limiting greenhouse-gas pollution from the largest sources,” she said.

Agence France-Presse/Getty ImagesSmoke stacks at a West Virginia coal-fired power plant.

The court also upheld EPA rules that drew on its 2009 finding, including greenhouse-gas emissions standards for cars that took effect beginning with the 2012 model year.

Unlike some other industries, auto makers support the Obama administration on the greenhouse-gas rules, saying it is easier to have a common national standard than to leave regulation to the 50 states, some of which would be likely to adopt their own rules if Washington didn’t.

A Ford spokeswoman said the auto maker is “supportive of one national framework” for regulating fuel-economy and tailpipe emissions. “We are committed to increasing the fuel economy of our vehicles,” she said.

On Tuesday, Ford presented its 2013 model lineup, stressing vehicles such as the hybrid version of the Fusion midsized sedan that, according to Ford, will go 47 miles on a gallon of gasoline, and a battery-powered Ford Focus said to offer the equivalent of 110 miles per gallon with no carbon-dioxide emissions.

Under the George W. Bush administration, the EPA contended it didn’t have the power to regulate greenhouse gases. But the Supreme Court ruled 5-4 in 2007 that the Clean Air Act not only gave the EPA such power, but obligated the agency to exercise it if greenhouse gases were found to be harmful.

After Mr. Obama’s EPA followed up on the high-court ruling with new regulations, industry groups sued, saying there was too much uncertainty about global warming for the agency to act as it did.

Tuesday’s ruling flatly rejected that contention. The opinion, issued jointly by three judges on the U.S. Court of Appeals for the District of Columbia Circuit, said the EPA “marshaled substantial scientific evidence” to support its findings. “The existence of some uncertainty does not, without more, warrant invalidation of an endangerment finding,” the court wrote.

Chief Judge David Sentelle, an appointee of President Ronald Reagan, and Judges Judith Rogers and David Tatel, both appointees of President Bill Clinton, issued the decision.

The ruling allows the EPA to move forward with additional efforts to limit greenhouse-gas emissions from industrial sources. The EPA is now working to make final its first set of national limits on carbon dioxide from new coal-fired power plants.

The standards, first proposed in March, are expected to make construction of new coal plants increasingly unlikely as power generators opt for natural gas.

In recent months, utilities have announced they plan to mothball dozens of coal-fired power plants, responding to EPA rules that restrict release of pollutants like mercury, in addition to greenhouse gases.

Plants burning natural gas often release about half as much carbon dioxide as plants burning coal, and plentiful new supplies of natural gas in the U.S. have made the fuel price-competitive.

Southern Co. and Duke Energy Corp. DUK +0.48% are building two “clean coal” power plants that will turn coal into a combustible gas to make electricity. But the cost of the plants—about $3 billion apiece—means that the technology is unlikely to be widely adopted.

The challengers could ask the full appeals court to rehear the case or seek Supreme Court review. Republican Attorney General Ken Cuccinelli of Virginia, one of the law’s challengers, said the state plans to appeal to the Supreme Court.

Such efforts, however, may face long odds. At several points in Tuesday’s ruling, the three-judge panel indicated it had little difficulty in rejecting many of the challengers’ arguments.

Among other things, some challengers said they wanted to block the EPA from phasing in the greenhouse-gas regulations. They said that phase-in, by easing the pain on companies, postponed the day when Congress would have to act to remove the burden more thoroughly.

The court said the companies didn’t have legal standing to make that argument and cited an episode of the old Saturday morning cartoon “Schoolhouse Rock” that explained the long and difficult journey for any bill. “As a generation of schoolchildren knows…[it’s] not easy to become a law,” the court said.

In other words, no one on this three judge panel remembers their seventh and eighth grade science classes either – -how soon we forget! What is it about “photosynthesis” supposedly “intelligent people” do NOT understand!